<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<div style="border: 1px solid red;height: 300px" ></div>
</body>
<script>
  window.onload=function(){
    alert(1)
  }
</script>
</html>
